How to Install Lighting in Plaster Ceilings

Cutting through plaster can lead to cracks if you're not careful.

Installing a light in a plaster ceiling isn't much different than installing it in a drywall ceiling, except you must take extra care to keep the plaster from cracking. Plaster has a tendency to chip and crack as you cut through it, especially in older homes. The plaster is applied over thin wooden slats called the lath, and you must cut through both the plaster and the lath to install the light.

1

Mark the light's location on the plaster side of the ceiling. Measure the size of the opening necessary to fit the light through the ceiling.

2

Draw a circle large enough to work with the light. Depending on the type of light you're installing, this is likely a fairly small hole, less than 4 inches in diameter. If you are hanging a chandelier, ensure the hole is small enough to be covered by the top cap.

3

Score along the circle line with a utility knife. Continue scoring the plaster until the center of the circle falls out.

4

Cut through the lath, using a jigsaw. Follow the same circle as the plaster. This should open the ceiling to the electrical wiring for the light fixture.

5

Turn off the electric for the light at the breaker box. Climb into the attic to access the wiring. Feed the lighting wires through a hole in the side of the light fixture's electrical box. Remove one of the hole covers by placing a screwdriver in the center of the cover and tapping it with a hammer, if necessary.

6

Screw the electrical box in place by putting it over the hole and screwing the box onto the lath. The screws should be at least 2 inches from the cut ends of the lath. Secure the side of the electrical box to a joist, if possible.

7

Climb a ladder and strip about 2 inches off the ends of the light wires inside the ceiling light electrical box. Connect the light fixture to the metal crossbar connector, using machine screws and a screwdriver.

8

Place the crossbar over the bottom of the light box and screw it into the holes in the bottom of the light box, allowing the light to hang down from the chain connected to the crossbar.

9

Find the hot electrical wire in the ceiling and match it with the hot wire in the light fixture. These are normally black or red. Wrap the ends together and screw a wire connector over the ends. Repeat with the neutral wires, which are often white. If one is not white, recognize it as a neutral wire by its silver tips instead of copper-colored or by looking for the wire with writing on it. Wrap the ground wire from the ceiling around a screw on the crossbar, then use a wire connector to attach it to the ground wire from the light fixture.

10

Push the wires into the light electrical box and slide the cover plate flush with the ceiling. Push up on the nut holding the cover plate in place.

Things You Will Need

Measuring tape

Utility knife

Jigsaw

Screwdriver

Hammer

Ladder

Wire stripper

Wire connectors

Plaster washers

Drywall screws

Joint compound

Sandpaper

Paint

Paintbrush

Tip

If you crack the plaster when you are cutting through it or when you're working on installing the light, secure the plaster around the crack to the lath using plaster washers and drywall screws. Cover them with joint compound, then sand it and paint it to match the rest of the ceiling.

If you're installing a light that's flush with the ceiling, you might not have a crossbar, but you should see holes in the base of the light fixture that line up with holes in the light electrical box. Connect the wires first, then connect the base of the fixture to the electrical box.

About the Author

Based outside Atlanta, Ga., Shala Munroe has been writing and copy editing since 1995. Beginning her career at newspapers such as the "Marietta Daily Journal" and the "Atlanta Business Chronicle," she most recently worked in communications and management for several nonprofit organizations before purchasing a flower shop in 2006. She earned a BA in communications from Jacksonville State University.